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(No Model.)

H. W. ROBIE.

SCREW JACK. No. 461,643. Patented Oot. 20, 1891.

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775212766866. cyiywfa?? UNITED STATES vPATENT' OFFICE.

HENRY WV. ROBIE, OF-PHILADELPI-IIA, PENNSYLVANIA, ASSIGNOR TO JOSEPH HAINES AND SAMUEL PRESTON JOHNS, BOTH OF SAME PLACE.

SCREW-JACK.

SPECIFICATION forming part of Letters Patent No'. 461,643, dated October 20, 1891.

Application filed April 29, 1891.

To all whom it may concern:

Be it known that I, HENRY W. ROBIE, a citizen of the United States, residing in the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful Improvements in Screw-Jacks, of which the following is a specification, reference being had to the accompanying drawings, forming part hereof.

My invention relates to screw jacks, the object of the invention being to provide a device of this character which shall be simple in its construction, easy of and effective in operation, strong'and durable, and one by which a heavy Weight may be raised with but a minimum expenditure of power, and relates particularly to that class of screw-jacks embodying a pedestal, a power-screw, and revoluble power-nut stationary against vertical 2o movement for elevating and lowering said screw, and means for continuously rotating said nut; and it consists in the several novel features of construction and combinations of parts hereinafter fully described, and specifi- 2 5 cally set forth in the claims.

lIn the drawings, Figure l is a perspective view of a jack constructed in accordance with my invention. Fig. 2 is a vertical sectional view of the same. Fig. 3 is a view of the 3o collar or yoke. Fig. t is a View of the double pawl; and Fig. 5 is an enlarged sectional view taken on the line a: 0c of Fig. 2.

Corresponding parts in the several figures are denoted by the same letters of reference.

Referring to the drawings, A represents the pedestal, which is made hollow with a smooth bore and iiaring at its lower end to form a wide base or support, and formed with a circumferential groove or channel a in its 4o side below its upper end, for a purpose more fully set forth.

B is a metal ring or washer resting on the y upper surface of the pedestal A, and is provided with a groove or channel b, to receive a series of anti-friction rollers or balls.

C represents a series of antifriction rollers or balls seated in said groove b, for a purpose hereinafter set forth.

D represents a power-nut formed with a 5o central opening, which is screw-threaded to receive the powerscrew E, and is provided Serial No. 390,953. (No model.)

with an inner shoulder d, having a circumferential groove or channel d to receive the upper surfaces of the balls C. This nut is further provided with a downwardly-extending circumferential iiange DX, which incloses the balls C and the upper end of the pedestal. This nut is held against vertical movement by one or more screws (ZX, which extend through the iiange D and have their ends 6o located in the groove or channel ct in the side of the pedestal, whereby the nut may be easily rotated and at the same time is held against vertical movement. This power-nut I) is further formed on its outer face with a circumferential series of teeth d?, which are located a slight distance from the upper end of the .n ut and adjacent to the flanged end thereof.

E represents the power-screw, which engages the threads of the power-nut and is 7o provided at its upper end with a head or rest e, upon which the object to be raised rests.

F represents a collar or yoke, which fits upon the power-nut and incloses the teeth of the latter. an extension f, having an opening fX and adapted to receive a double pawl or detent G, preferably of the construction shown in Fig.

4, which engages the teeth of the powernut and extends beyond the collar or yoke to the 8o outside thereof.

g is a spiral spring or the like located between the upper surface of the pawl and the inner surface of the yoke or collar above it, and its object is to maintain the pawl in a 8 5 horizontal position for engagement with the teeth of the power-nut.

Formed integral with or removably secured to the outer end of the pawl or detent is a socket-joint H, and when made separate from 9o the pawl is preferably secured thereto by a screw h, which passes through the socket and into the' pawl, and is adapted to receive a handle or lever I, by means of .which the pawl or detent may be operated t0 revolve the nut. 95 By this arrangement it will be seen that the nut may be revolved in either direction to raise or lower the power-screw, as desired, and that the necessity of removing the handle and replacing, as is necessary in other jacks, roo

is avoided.

The collar or yoke F is held in place by l This collar or yoke is formed with i means of a ring J, which tits upon the upper end of the power-nut and is secured thereto by screws j, which extend through the ring and into said nut near the upper edge of the same.

The ring or washer Il may be dispensed with and a groove or channel formed in the upper surface of the pedestal to receive the series of anti-friction rollersor balls to the same end.

I do not Wish to be understood as confining myself to the exaet construction of parte` herein shown and described, as it is obvious that many details of Construction may be adopted without departing' from the spirit of my invention.

Having thus described my invention, I olaiml. In a screw-jack, the combination,with a pedestal and power-screw, of a power-nut supported on the upper end of the pedestal, said nut having a downwardlyextending flange to hold it against lateral movement, and a screw exten ding through said flange and working in a circumferential groove in the pedestal to prevent vertical movement, a series of anti-friction rollers or balls between Said pedestal and power-nut, a circumferential series of teeth on the face of said nut, a Collar having an opening and inelosing said teeth, a pawl or detent fitting said opening and adapted to engage said teeth, a spring between said pawl and collar, and a ring secured upon the upper end of the power-nut, as set forth.

2. In a se1ewjaek, the Combination, with a pedestal and power-screw, of a power-nut having a series of teeth on its outer face, a collar having,r an opening and inelosing said teeth, a pawl or detent fitting` said opening and adapted to engage said teeth, a spring between said pawl and collar, and a ring secured upon the upper end of the power-nut, as set forth.

In testimony whereofI have hereunto signed my name this 29th day of April, A. D. 138).

HENRY \V. ROBIE.

In presence of* JOHN JOLLEY, Jr., JOSEPH HAnvEs. 

